[1] Univ Iowa, Dept Internal Med, Carver Coll Med, Iowa City, IA 52242 USA
[2] Mayo Clin, Div Pediat Infect Dis, Rochester, MN USA
[3] Hosp St Raphael, Infect Dis Sect, New Haven, CT 06511 USA
[4] Wake Forest Univ, Dept Internal Med, Baptist Med Ctr, Winston Salem, NC 27109 USA
[5] Univ Iowa, Coll Publ Hlth, Iowa City, IA USA